The prior art includes a number of different firearm safety arrangements. These safety arrangements can be classified in various groups, namely:
1. The mechanical key operated type, such as disclosed in U.S. Pat. No. 4,512,099 (Mathew), U.S. Pat. No. 4,509,281 (Dreiling et al), U.S. Pat. No. 3,673,725 (Cravener).
2. The magnetically operated key type, such as found in U.S. Pat. No. 4,154,014 (Smith).
3. The electronic remote control type, having a separate controlling transmitter and a receiver located on the firearm, such as shown in U.S. Pat. No. 4,682,435 (Heltzel), U.S. Pat. No. 4,563,827 (Heltzel), U.S. Pat. No. 3,939,679 (Barker et al), U.S. Pat. No. 4,488,370 (Lemelson), U.S. Pat. No. 4,189,712 (Lemelson), U.S. Pat. No. 4,354,189 (Lemelson).
4. The mechanical combination lock type, such as described by U.S. Pat. No. 4,499,681 (Bako et al).
5. The electronically programmable key lock type, such as disclosed by U.S. Pat. No. 4,457,091 (Wallerstein).
Most of the above devices require substantial changes to be effected to a firearm prior to fitting the safety arrangement.
It is an object of the invention to provide a safety device which can be fitted to a firearm requiring a minimum of changes to such a firearm.